Updated: March 2, 2019
Vitamin A is a fat-soluble vitamin that is naturally present in many foods. Vitamin A is important for normal vision, the immune system, and reproduction. Vitamin A is required for the proper development and functioning of our eyes, skin, immune system, heart, lungs, kidneys and various parts of our bodies.
Vitamin A is likely safe for most people when taken by mouth or given as a shot into the muscle in amounts less than 10,000 IU daily. However, it is possibly unsafe if taken in high doses orally. Taking high doses of vitamin A supplements might increase the chance of death from all causes and possibly other serious side effects. Higher doses might increase the risk of osteoporosis and hip fracture, particularly in older people. Adults who eat low-fat dairy products, which are fortified with vitamin A, and a lot of fruits and vegetables usually do not need vitamin A supplements or multivitamins that contain vitamin A.
Long-term use of large amounts of vitamin A might cause serious side effects including fatigue, irritability, mental changes, mild fever, excessive sweating, anorexia, stomach discomfort, nausea, vomiting and many other side effects. Taking too much vitamin A can increase the risk of osteoporosis and hip fracture in women who have passed menopause. Vitamin A is safe for children when taken in the recommended amounts. The recommended dose of vitamin A that are safe for children are based on age and is given below:
It is unsafe when taken in high doses orally by children. When taken more then the recommended dose, it may have side effects that include irritability, sleepiness, vomiting, diarrhea, loss of consciousness, headache, vision problems, peeling skin, increased risk of pneumonia and diarrhea, and other problems. Precautions should be taken while taking vitamin A supplement for the below conditions:
Vitamin A is safe for pregnant or breast-feeding women when taken in recommended dose of less than 10,000 IU per day. When taken more then the recommended dose can cause birth defects. It is especially important for pregnant women to monitor their intake of vitamin A from all sources during the first three months of pregnancy. Forms of vitamin A are found in several foods including animal products, primarily liver, some fortified breakfast cereals, and dietary supplements.
Drinking alcohol may increase harmful effects on the liver because of vitamin A.
People who are anemic and have low levels of vitamin A might need to take iron along with a vitamin A supplement to treat this condition.
People with conditions that affect fat absorption, such as celiac disease, short gut syndrome, jaundice, cystic fibrosis, pancreatic disease, and cirrhosis of the liver, are not able to absorb vitamin A properly. In these cases, vitamin A preparations that are water-soluble can be used to improve vitamin A absorption.
This is a type of high cholesterol that might increase the chance of vitamin A poisoning. Do not take vitamin A if you have this condition.
Intestinal infections such as hookworm can reduce how much vitamin A the body absorbs.
Iron deficiency might affect the ability of your body to breakdown and use vitamin A.
Too much vitamin A might make liver disease worse. Do not take vitamin A if you have liver disease.
In people with severe protein malnutrition, taking vitamin A might result in having too much vitamin A in the body.
Zinc deficiency might cause symptoms of vitamin A deficiency to occur. Taking a combination of vitamin A and zinc supplements might be necessary to improve this condition.
Some medications for skin conditions have vitamin A effects. Taking vitamin A pills and these medications for skin conditions could cause too much vitamin A effects and side effects. So, do not take this combination.
Vitamin A can interact with some antibiotics. Taking very large amounts of vitamin A along with some antibiotics can increase the chance of a serious side effect called intracranial hypertension. But taking normal doses of vitamin A along with tetracyclines may not cause this problem. Do not take large amounts of vitamin A if you are taking antibiotics like demeclocycline (Declomycin), minocycline (Minocin), and tetracycline (Achromycin).
Taking large amounts of vitamin A might harm the liver. Taking large amounts of vitamin A along with medications that might also harm the liver can increase the risk of liver damage. Do not take large amounts of vitamin A if you are taking a medication like acetaminophen (Tylenol and others), amiodarone (Cordarone), carbamazepine (Tegretol), isoniazid (INH), methotrexate (Rheumatrex), methyldopa (Aldomet), fluconazole (Diflucan), itraconazole (Sporanox), erythromycin (Erythrocin, Ilosone, others), phenytoin (Dilantin), lovastatin (Mevacor), pravastatin (Pravachol), simvastatin (Zocor), and many others.
Warfarin (Coumadin) is used to slow blood clotting. Large amounts of Vitamin A can also slow blood clotting. Taking Vitamin A along with warfarin (Coumadin) can increase the chances of bruising and bleeding. Make sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.
The amount of vitamin A you need depends on your age and reproductive status. Vitamin A dosage is most commonly expressed in IU, but dosage in micrograms is sometimes used. Eating 5 servings of fruits and vegetables per day provides about 50% to 65% of the adult RDA for vitamin A
Recommended Dietary Allowance (RDA) levels for adults in different conditions are:
Tolerable Upper Intake Levels (UL) for vitamin A have also been established. The UL is the highest level of intake that a person can take with no risk of harmful effects. The ULs for vitamin A are for preformed vitamin A (retinol) and do not include provitamin A carotenoids. These include:
Weekly dose of 200,000-300,000 IU of vitamin A has been used for 6-12 months
Weekly doses of 23,000 IU of vitamin A have been used before, during, and after pregnancy.
Weekly doses of 23,000 IU of vitamin A have been used before and during pregnancy.
Weekly doses of 23,000 IU of vitamin A have been used before, during, and after pregnancy. It seems to work best if taken in combination with 35 mg of zinc daily in women who also have low levels of zinc.
Daily doses of 15,000 IU of vitamin A, sometimes along with 400 IU of vitamin E daily, has been used. Recommended Dietary Allowance (RDA) levels for children in different conditions are:
Tolerable Upper Intake Levels (UL) for vitamin A have also been established. The UL is the highest level of intake that a person can take with no risk of harmful effects. The ULs for vitamin A are for preformed vitamin A (retinol) and do not include provitamin A carotenoids. These include:
Vitamin A 100,000 to 200,000 IU orally for at least two doses has been used in children less than 2 years-old.
Vitamin A is found naturally in many foods and is added to some foods, such as milk and cereal. Therefore you can get recommended amounts of vitamin A by eating a variety of foods. These include:
Most multivitamin-mineral supplements contain vitamin A. Dietary supplements that contain only vitamin A are also available.
Vitamin K is actually a group of compounds and the name vitamin K comes from the German word 'Koagulationsvitamin.'
Vitamin A is likely safe for most people when taken by mouth or given as a shot into the muscle in amounts less than 10,000 IU daily.
Vitamin A is a fat-soluble vitamin that is naturally present in many foods.
Vitamin D is required for the regulation of the minerals calcium and phosphorus in the body.
The liquid remaining after milk has been curdled and strained is known as whey.
The best way to get enough of omega-3 is to include foods that are rich in omega-3 in your diet, like fatty fish,walnut etc.
An energy drink is a type of drink that contains sugar and stimulant compounds, usually caffeine.
Meal replacement shakes are prepared to provide the nutrition of a full meal, just like protein shakes